Cable hold-down anchor device



June 4, 1963 B. HILLBERG 3,091,897'

CABLE HOLD-DOWN ANCHOR DEVICE Filed Aug- 19, 1959 3 Sheets-Sheet 1 FIG.2

INVENTOR.- BROR HILL RG BY m June 4, 1963 B. HILLBERG CABLE HOLD-DOWNANCHOR DEVICE Filed Aug. 19, 1959 3 Sheets-Sheet 2 INVENTOR.

BROR HILLBERG BY ATT'Y June 4, 1963 B. HILLBERG CABLE HOLD-DOWN ANCHORDEVICE 3 Sheets-Sheet 3 Filed Aug. 19. 1959 INVENToR.- BROR H H LBERG BYUnited States Patent O 3,091,897 CABLE HOLD-DOWN ANCHOR DEVICE BrorHillberg, Franklin Park, Ill., assigner, by mesne assignments, toSuperior Concrete Accessories, inc., a corporation of Eelaware FiledAug. 19, 1959, Ser. No. 834,827 2 Claims. (Cl. Sli- 130) The presentinvention relates to concrete hardware and has particular reference to ahold-down anchor device by means of which the tensioning cables whichare embedded in a prestressed concrete -girder or the like may be heldtaut under tension and in their proper relative positions within thegirder form during initial pouring and subsequent hardening `or settingof the concrete so that when the tension in the cables is relievedyafter the concrete has become set and the projecting ends of the cablesevered from the ends of the girder, the material of the girder willremain prestressed, thus providing a structure which possesses greaterstrength than conventional girders which are not prestressed in thismanner.

Girders of this type with which the present hold-down anchor device isassociated are `of the portable type, which is to say, they may bepreformed as a composite unit and, thereafter, transported bodily to ascene of installation. Such girders may assume various cross sectionalshapes and, for exemplary purposes herein, the hold-down anchor devicehas been illustrated in connection with the construction of a girderwhich is generally of I-shape in cross section and which will, forconvenience of description, hereinafter be referred to as an I-beam. ltwill be understood, however, that the present hold-down anchor devicemay be found useful .in the formation of concrete girders having a widevariety `of other shapes, `such as channels, rectangular beams, and thelike. irrespectively, however, of the particular use to which theinvention may be put, the essential eatures :thereof are at all timespreserved.

The present invention is designed as an improvement over the hold-downanchor device shown and described in my co-pending application SerialNo. 832,862, filed on August l0, 1959', now U.S. Patent No. 3,006,114dated Oct. 3l, 1961, and entitled Hold Down Anchor Device for theEmbedded Cables of Prestressed Concrete Girders. In such application,there has been shown a holddown -anchor device which has beenillustrated Vas being applied to a typical girder installation with afull description of the girder being made to facilitate a more completeunderstanding of the invention. in the present instance, no suchdetailed illustration or description of the girder assembly is made andreference may be had to the above co-pending application for a fullunderstanding of the speciiic nature yof the -girder, it being deemedsufficient herein merely to illustrate the novel hold-down anchor devicein its immediate embedded environment within the concrete of the girder.

ln the construction of prestressed concrete girders of the type brieflyoutlined above, the tensioning cables, of which there may be arelatively large number, are ordinarily strung longitudinally throughthe hollow ygil-der form in different but generally longitudinallyextending directions. Certain yof the cables may be strung linearly andaxially through the -girder dorm in straightline fashion while othersmay deviate from such axial alignment at various angles. For example,where prestressed concrete I-beams having an upper head portion, a-lower base portion, and a narrow interconnecting web portion, lareconcerned, certain `of Ithe cables are strung through the concretegirder form so that they extend inwardly from the ends of the girder inthe head portion thereof and are inclined downwardly so that they passthrough the narrow web portion of the girder and enter the base portionthereof, after which they extend longitudinally in straight-line fashionthrough the base portion of the girder in the medial regions of thelatter. The cables are thus caused .to make a dip, so to speak, as theypass through the girder from one end to the other so that the endregions of the cables are embedded in the head portion of the girderwhile the medial regions `thereof are embedded in the base portion ofthe girder. Certain other cables are caused to pass through the baseportion of the girder outside the transverse contines of the web portionin straight-line axial fashion. These latter cablesrequire no hold-downanchoring devices since, when they are placed under tension by thehydraulic tensioning mechanism, they assume their straight-linepositions. However, those cables which are lstrung through the form atvarying angles require hold-down devices so that when the hydraulictensioning means is set into operation, the cables` will be drawn tauti-n their predetermined directions of extent through the girder form.Hold-down anchor devices of the type shown in my co-pending application,above referred to, and in the present application are designed tofacilitate proper threading of the various cable strands through thegirder form with a minimum eff-ort on the part ofthe operator so thatafter the threading operation h-as been completed, it is merelynecessary to'apply tension to the cables sok that they will be drawntaut and assume their respective desired directional extent through thegirder form preparatory to concrete pouring operations.

It is among the principal objects of the present invention to provide aholddown anchor device of the general character set forth above andwhich is maintained in Iposition within the concrete by means 'of aconventional coil bolt socket and a cooperating 'lag screw, the socketbeing secured in the anchor device assembly in a more expeditious mannerthan has heretofore been possible, the method of yassembly involvingprojection welding of the various parts with the attainment of closerweld points.

A further object of the invention is to provide a holddown anchor deviceof the type shown and described,l in the `above-mentioned co-pendingapplication :and which may be constructed in a wide variety of sizesWithout appreciably increasing the size and weight ofthe individualcomponents ofthe assembly.

Yet another object of the invention, in a hold-down anchor device ofthis sort, is to provide a structure which utilizes lighter gaugematerials than has heretofore been employed, yet which .aifords the samestrength and rigidity as devices of corresponding size which aredesigned for the same purpose.

A still further` object of the invention is -to provide a hold-downanchor device having associated therewith, novel retaining means formaintaining the various cables to which the device is applied in theirproper spacedpositions against dislodgment during cable-tighteningopera-v tions. A similar related object of the invention is toprovidesuch a device wherein the cable-retaining means .are in the form ofremovable keeper devices, which, by their use, eliminate the necessityof threading the cables endwise through the device. By such anarrangement, it is possible to string the cables across the terminalsupports therefor and, thereafter, apply the cables to the hold-. downanchor device at the medial regions of the cables.

An additional object of the invention is to provide a. hold-down anchordevice of the type employingrspacedside supports, across which thereextend a series of traction assemblies for direct assimilation of thecable thrust, together with a series Iof spacer elements or struts bymeans of which the side supports are maintained, in their proper spacedrelationship, certain of the spacer struts also serving the function of:affording guideways for the removable keeper devices. l

Finally, it is `an obiect of the invention to provide a hold-down anchorassembly wherein a major portion of the components thereof are formed ofsheet and rod stock thereby contributing to economy of manufacture.

Other objects and advantages of the invention will become more readilyapparent .as the following description ensues.

In the accompanying three sheets of drawings forming a part of thisspecilication, a preferred embodiment of the invention has been shown.In these drawings:

FIG. l is a front elevational View of a hold-down anchor deviceconstructed in accordance with the principles of the present invention;

FIG. 2 is a side elevational view of the structure shown in FIG. l;

FIG. 3 is a rear elevational View of the hold-down anchor device;

FIG. 4 is a side elevational view of the structure shown in FIG. 3;

FIG. 5 is an enlarged fragmentary perspective view of the lower portionof the hold-down anchor device;

FIG. 6 is a top plan view of the hold-down anchor device;

FIG. 7 is a bottom plan view of the hold-down anchor device;

FIG. 8 is a detail perspective view on an enlarged scale of a coilsocket and side plate assembly forming a part of the present hold-downanchor device;

i FIG. 9 is a fragmentary sectional view taken substantially centrallyand longitudinally through a concrete girder form assembly showing thehold-down anchor device operatively installed therein;

FIG. 10 is a sectional view taken substantially along the line 10-10 ofFIG. 9; and

FIG. 11 is a sectional view taken substantially along the line f11-1-1of FIG. 9.

Referring now to the drawings in detail, and in particular to FIGS. 9 tol1, inclusive, a fragmentary portion of a prestressed concrete girderutilizing a hold-down anchor device constructed in accordance with theprinciples of the present invention has been designated in its entiretyat 10. Although the outline of the girder 10 has not vbeenillustratedherein, it may be assumed forpurposes of description of thelfunction `of the hold-down anchor of the invention that the girder isin the form of an I-bearn through which a plurality of tensioningstrands or cables 12 extend longitudinally as shown in FIG. 9, thestrands, insofar as each hold-down anchor device is concerned, beingarranged in pairs transversely of the girder as shown in FIG. l0, andthe various pairs being arranged in superimposed relationship as shownin FIG.

9. For illustrative purposes herein, only one set of super- V imposedpairs of cables appear in the various views of the drawings, but it willbe understood that, utilizing trans- Versely displaced hold-down anchordevices, plural sets of cables may extend through the girder .16.

vThe complete concrete girder 10 may have embedded therein variousaccessory inserts such as lifting hooks,

stirrups, and the like, as well as linearly straight tensioning cables,as is well known in the art and none of which have been illustratedherein. The invention is primarilyv strands being iirrnly embedded inthe surrounding mass of concrete and being initially positioned in theconcrete girder or I-beam form by means of a series of hold-down anchordevices, each of which has been designated in its entirety at 14. Theanchor devices 14 are in the form of composite anchor assemblies, eachassembly being designed to accommodate a plurality of the cables l2.

As shown in FIG. 9, the cables 12 extend from the upper regions of theIgirder I0 at one end of the latter, inwardly and downwardly on anincline as at 16 through the web portion of the girder and into the baseportion thereof where they are engaged by one of the holddown anchordevices 14, after which these strands extend horizontally as at 13 alongthe base portion and into engagement with a second hold-down anchordevice 14. From the second device 14, the strand extend upwardly on anincline as at 20 toward the other end of the girder and pass through theweb portion and into the head portion from whence they emerge from thegirder. As best seen in FIG. l0, 4the cable strands 12 are arranged intwo vertical tiers. Additional groups of strands, also held in positionby anchor devices, such as those shown at 14, may be provided on eitherside of the illustrated group of strands, if desired, although only onesuch group of strands has been disclosed herein.

The speciic nature of the previously described prestressed concretegirder assembly forms no part of the present invention and no claim ismade herein to any novelty in connection with the girder, the novelty ofthe present application residing rather in the construction of thevarious hold-down devices 14 by means of which the cables are initiallyheld in their proper directional orientation Within the concrete girderform preparatory to pouring of the concrete.

Referring now to FIGS. l to 8, inclusive, wherein one of the hold-downanchor assemblies 14 has been illustrated in detail, each assemblyinvolves in its general organization a pair of composite three-pieceside members 22, these side members being of identical construction andeach consisting of a generally at, rectangular plate 2d, and twoattachment rods 26. The plates 24 are formed of relatively light gaugesheet metal stock and each plate is formed with a plurality of holes 28therethrough, the holes being arranged in a vertical row and serving apurpose which will be made clear presently.

The two rods 26 are in the form of short lengths of rod stock and theyare Welded along portions of their extent to one face of the plate 24 inthe vicinity of the opposite longitudinal edges of the plate in such amanner as to overlap Ithe plate and extend an appreciable distance belowthe lower edge of the plate. 'Ihe portions of the rods 26 which overhangthe plates 24 are designated at 30 and such portions constituteanchoring fingers by means of which the entire plate assembly 22 as awhole may be welded yto a short length 32 of closely wound helical coilstock, the various convolutions of which provide a series of internalcoil threads adapted to receive therein the threaded end 34 of a lagscrew 36 by means of which the anchor device as a whole may be athxed inposition on the base member of the concrete girder form, as will bedescribed subsequently. 'Ihe helical coil thus serves to maintain thelower adjacent ends of the two side plate assemblies 22 in their properspaced relationship.

`In order to enhance the welded bond between the various rods 26 and thefaces of the plates 24 to which they are attached, the two plates areribbed or corrugated as at 39 along their marginal edges, as best seenin FIG. 8. Such corrugations in the plates 24 enable the various partsto be secured together by projection welding as distingushed from arcwelding since the various ribs make for closer weld areas than couldotherwise be obtained.

The hold-down anchor device illustrated herein has, purely forillustrative purposes, been designed to accommodate the anchoring of sixtiers of paired, vertically disposed cable strands 12 and, accordingly,the side plates proper 24 are each formed with six of the verticallyaligned holes 28, the various holes in the two plates being transverselyaligned in pairs across the anchor assembly, as best seen in FlG. 3.Each pair of ltransversely aligned holes 2S receives therethrough atraction pin lila The pins 49 may be in the form of conventional rivets,the shank portions 42 of which have been threaded as at 44 adjacenttheir distal ends. The pins 4t) project loosely through the holes Z andare freely rotatable therein. Interposed between the enlarged headportion 46 of each pin 4d and the adjacent side plate 24 and freelyrotatable on each pin is a roller Sil. On the other side of the assemblyexteriorly of the plate 2d, the shank portion 42 of each pin carries asecond roller 52. A nut 54 is threadedly received on the threaded end 44of the pin and serves to prevent removal of the roller 52 from the pin.The extreme end of the threaded portion 4d is peened or otherwisedeformed as at 5d to prevent removal of the nut 54. rThe nut 54 is nottightened on the threaded portion of the pin, but is left free to rotateor oat, so to speak, yon this portion. Thus, at no time will either ofthe two rollers Sil or 52 bind against the side plates 24 and the tworollers will always be free to rotate during cable tensioningoperations.

In order to maintain the medial and distal or upper end regions `of theside plates 24 properly spaced from each other and in parallelism, aseries of vertically spaced short struts 60 (FIGS. 2, 3 and 4) arewelded at their ends to the adjacent edges of the plates 24 on one sideof the device. On the other side of the device, a similar series ofstruts 62 having looped ends 66 (see also FIGS. 6 and 7) are welded tothe adjacent edges of the plates 24.

As best seen in FIGS. 9, l0 and ll, the various rollers 59 and 52 areadapted to receive therebeneath the cable strands 12 in any givenconcrete form installation and, accordingly, in order to bias the cablestrands within the contines of the various rollers, Ithe rollers are ofthe grooved type as shown in FIGS. l and 3. In order to retain the cablestrands in position beneath the rollers and prevent slipping of thecable strands sideways from the rollers during cable tensioningoperations, a pair of keeper rods 70, one for each side of thestructure, are provided. These keeper rods are in the form of elongatedlengths of rod stock having short laterally turned end portions 72. Thekeeper rods are threaded through the looped ends do of the struts 62 onopposite sides ci the assembly, these looped ends being in verticalalignment for reception of the rods. The keeper rods 7d are looselydisposed within the loops d6 and the upper laterally turned ends 72 ofthe rods are adapted to be loosely supported on the uppermost loops 66in the series. Each keeper rod 7G, in combination with the adjacent sideplate 24, serves to confine the cable strand within narrow transverselimits and to retain the cable strand in vertical register with theroller which is immediately thereabove.

In the installation and use of the herein described holddown anchordevice or assembly I4, holes such as have been shown at 8l? in FIG. 9are formed in the bottom or base member 8?; of the concrete girder formin the regions Iwhere it is desired to install the various devices 14.The lag screws 36 are passed upwardly through the holes Sil and arethreadedly received in the helical coil members or sockets 32. When thelag screws 36 are tightened, the tour lower ends of the rods 26 restsquarely on the base or bottom member 82 so that the anchor device 14 asa whole extends vertically and is rigidly secured within the emptyconcrete form between the form side walls.

Immediately prior to application of the various cable strands l2 Vto thehold-down anchor devices within the concrete form, the two keeper rods'70 are ywithdrawn from the various aligned looped ends 66 of the spacerstruts 62 and the medial regions of the untensioned cable strands i2 arehookedf so to speak, beneath the various rollers as shown in FIG. l0,after which the keeper rods 7d may be replaced by threading them throughthe aligned looped ends 66 of the stru-ts 62. Thereafter, the cables 16may be drawn taut by the usual hydraulic tensioning mechanism so thatthe medial regions of the cables will underlie and bear upwardlytractionally against the respective rollers immediately thereabove. Thecables will then assume the positions wherein they are shown in FIG. 9preparatory to pouring ofthe concrete into the girder form.

After the concrete has been poured and allowed to become set, the lagscrews 36 may be unthreaded from the various coil anchors or sockets 32and withdrawn from the form assembly. Finally, the form assembly may beknocked down and the projecting or protruding ends of the various cablestrands severed ilus'h with the ends of the girder.

While one specific and preferred form of hold-down anchor device bymeans of which the principles of the invention may be carried out hasbeen illustrated and described herein, it will be understood that thisform of the device does not by any means indicate the only formcontemplated. The form illustrated herein is only one which has beendeveloped for commerci-al application of the invention and, therefore,the invention is not to be limited to the details described since thesemay be modified within the scope of the appended claims withoutdeparting from the spirit of the invention.

Having thus described the invention what I claim as new and desire tosecure by Letters Patent is:

l. A hold-down anchor device for positioning the tensioning cables of aprestressed concrete girder within a girder form preparatory to concretepouring operations, said hold-down anchor device comprising, incombination, a pair of spaced, generally parallel, side members, eachside member including a vertically elongated llat plate of sheet metalstock and a pair of transversely spaced parallel vertical supportingrods extending along the marginal edge regions of the plate andoverhanging the lower edge of the plate so as to present portions whichdepend below lthe plate, said rods being secured to the same side of theplate by vwelding a closely-wound helical coil of rod stock interposedbetween the depending portions of the rods of each plate and secured bywelding thereto along axial lines of tangency, said coil being formedwith an internally threaded bore adapted to receive ltherein thethreaded end of a lag bolt whereby the side members may be secured tothe base support of the girder form within the contines of the form,said side plates being formed with a series of opposed pairs of holestherein with the various pairs being spaced progressively along the sideplates upwardly from said coil, a traction pin received through eachpair of opposed holes and having its opposite ends projecting outwardlybeyond the remote sides of said side plates, cable-engaging rollers insubstantial vertical alignment mounted on the projecting portions ofeach end of the traction pins and adapted to overlie and tractionallyengage a plurality of the tensioning cables so as to receive the upwardthrust thereof and space the same from said base support at the pointsof contact therewith when the cables are drawn taut, a plurality ofvertically spaced elongated struts, each disposed transversely of theadjacent vertical side edges of said plates and terminating at each otits ends in looped portions in substantial vertical alignment, saidportions lying substantially in a plane common with the outer verticalfaces of the cable-engaging rollers, said struts being secured to saidplates and, in combination with said coil, serving to maintain the sidemembers in their spaced parallel relationship, and a keeper rodextending through the aligned looped portions on each end of the strutsand removably seated therein, said keeper rods, in combination fwith theadjacent side plates being adapted to conline therebetween the variouscables so as to maintain the same in vertical register with saidrollers.

References Cited in the le of this patentV UNITED STATES PATENTS WitteNov. 12, 1907 White Dec. 3l, 1907 Murray Dec. 30, 1924 Schenk Nov. 30',1937 Fearon et al. Apr. 18, 1950 8 FOREIGN PATENTS 485,552 Italy Oct.14, 1953 561,555 Italy Apr. 23, 1957 5 OTHER REFERENCES RichmondCatalogue, published 1943 by Richmond Screw Anchor Co. Inc., Brooklyn, NY., page 15, item: F. M-Flange Hanger.

Concrete, page 60, September 1957.

10 Construction Methods and Equipment, pp. 102; 103

and 104; May 1958. Y

Publication: Holddown Anchors for Pretensioned-Prestressed Concrete bySuperior Concrete Accessories, Inc., Franklin Park, Ill., dated Dec. 2,1957.

1. A HOLD-DOWN ANCHOR DEVICE FOR POSITIONING THE TENSIONING CABLES OF APRESTRESSED CONCRETE GIRDER WITHIN A GIRDER FORM PREPARATORY TO CONCRETEPOURING OPERATIONS SAID HOLD-DOWN ANCHOR DEVICE COMPRISING, INCOMBINATION, A PAIR OF SPACED, GENERALLY PARALLEL, SIDE MEMBERS, EACHSIDE MEMBER INCLUDING A VERTICALLY ELONGATED FLAT PLATE OF SHEET METALSTOCK AND A PAIR OF TRANSVERSELY SPACED PARALLEL VERTICAL SUPPORTINGRODS EXTENDING ALONG THE MARGINAL EDGE REGIONS OF THE PLATE ANDOVERHANGING THE LOWER EDGE OF THE PLATE SO AS TO PRESENT PORTIONS WHICHDEPEND BELOW THE PLATE, SAID RODS BEING SECURED TO THE SAME SIDE OF THEPLATE BY WELDING A CLOSELY-WOUND HELICAL COIL OF ROD STOCK INTERPOSEDBETWEEN THE DEPENDING PORTIONS OF THE RODS OF EACH PLATE AND SECURED BYWELDING THERETO ALONG AXIAL LINES OF TANGENCY, SAID COIL BEING FORMEDWITH AN INTERNALLY THREADED BORE ADAPTED TO RECEIVE THERIN THE THREADEDEND OF A LAG BOLT WHEREBY THE SIDE MEMBERS MAY BE SECURED TO THE BASESUPPORT OF THE GIRDER FORM WITHIN THE CONFINES OF THE FORM, SAID SIDEPLATES BEING FORMED WITH A SERIES OF OPPOSED PAIRS OF HOLES THEREIN WITHTHE VARIOUS PAIRS BEING SPACED PROGRESSIVELY ALONG THE SIDE PLATESUPWARDLY FROM SAID COIL, A TRACTION PIN RECEIVED THROUGH EACH PAIR OFOPPOSED HOLES AND HAVING ITS OPPOSITE ENDS PROJECTING OUTWARDLY BEYONDTHE REMOTE SIDES OF SAID SIDE PLATES, CABLE-ENGAGING ROLLERS INSUBSTANTIAL VERTICAL ALIGNMENT MOUNTED ON THE PROJECTING PORTIONS OFEACH END OF THE TRACTION PINS AND ADAPTED TO OVERLIE AND TRACTIONALLYENGAGE A PLURALITY OF THE TENSIONING CABLES SO AS TO RECEIVE THE UPWARDTHRUST THEREOF AND SPACE THE SAME FROM SAID BASE SUPPORT AT THE POINTSOF CONTACT THEREWITH WHEN THE CABLES ARE DRAWN TAUT, A PLURALITY OFVERTICALLY SPACED ELONGATED STRUTS, EACH DISPOSED TRANSVERSELY OF THEADJACENT VERTICAL SIDE EDGES OF SAID PLATES AND TERMINATING AT EACH OFITS ENDS IN LOOPED PORTIONS IN SUBSTANTIAL VERTICAL ALIGNMENT, SAIDPORTIONS LYING SUBSTANTIALLY IN A PLANE COMMON WITH THE OUTER VERTICALFACES OF THE CABLE-ENGAGING ROLLERS, SAID STRUTS BEING SECURED TO SAIDPLATES AND, IN COMBINATION WITH SAID COIL, SERVING TO MAINTAIN THE SIDEMEMBERS IN THEIR SPACED PARALLEL RELATIONSHIP, AND A KEEPER RODEXTENDING THROUGH THE ALIGNED LOOPED PORTIONS ON EACH END OF THE STRUTSAND REMOVABLY SEATED THEREIN, SAID KEEPER RODS, IN COMBINATION WITH THEADJACENT SIDE PLATES BEING ADAPTED TO CONFINE THEREBETWEEN THE VARIOUSCABLES SO AS TO MAINTAIN THE SAME IN VERTICAL REGISTER WITH SAIDROLLERS.